Cylindrical-shaped clubs are used as security devices and also find use in fishing. Large game fish can be dangerous when placed on the deck of a boat. In regulated competition such as tournaments sanctioned by I.G.F., it is not permitted to kill a fish by shooting. Anglers are allowed to stun or kill the fish by clubbing. Many fishermen use a steel club for this purpose such as a length of rod or flat stock. However, the fish is alive and squirming. It is not uncommon for the steel rod to miss the fish or glance off the fish and hit the deck, the railing or body of the boat. The steel rod can break or bend the rail or can puncture or fracture the fiberglass coating or shell of the boat. Many times chunks are removed from the deck or body of the boat. Also when the rod hits a hard surface, the force will transmit up the arm of the fisherman and can cause trauma to his wrist, elbow or shoulder. Iron clubs can rust in a marine environment transferring rust stains to the boat. They also rattle on the deck on a boat.
Aluminum baseball bats or a shorter fish bat made of aluminum have also been used to stun or kill fish. The baseball bat is too long for one person to hold the line in one hand and wield the bat with the other. The aluminum fish bat is shorter but is light and transfers excessive vibration and recoil to the arm of the user. The round grip of a bat provides a less secure grip than a flatter grip especially in a slippery hand wet with sea water.
Clubs used for security protection such as billy clubs also develop recoil when a solid object is hit. Covering a metal club with an elastomer sheath should reduce recoil. However, there is a large difference in the coefficient of expansion between metal and rubber and the adhesion between metal and elastomer is poor. There is a differential in the length of the sheath and metal rod during deflection and after many cycles of deflection and vibration from impact, the elastomer sheath can separate from the rod.